Rigid Renewable Polyester Compositions having a High Impact Strength and Tensile Elongation

ABSTRACT

A thermoplastic composition that contains a rigid renewable polyester and a polymeric toughening additive is provided. The toughening additive can be dispersed as discrete physical domains within a continuous matrix of the renewable polyester. An increase in the deformation force and elongational strain causes debonding to occur in the renewable polyester matrix at those areas located adjacent to the discrete domains. This can result in the formation of a plurality of voids adjacent to the discrete domains that can help to dissipate energy under load and increase impact strength. To even further increase the ability of the composition to dissipate energy in this manner, an interphase modifier may be employed that reduces the degree of friction between the toughening additive and renewable polyester and thus enhances the degree and uniformity of debonding.

BACKGROUND OF THE INVENTION

Injection molding is commonly used to form plastic articles that arerelatively rigid in nature, including containers, medical devices, andso forth. For example, containers for stacks or rolls of pre-moistenedwipes are generally formed by injection molding techniques. One problemassociated with such containers, however, is that the molding materialis often formed from a synthetic polymer (e.g., polypropylene or HDPE)that is not renewable. The use of renewable polymers in an injectionmolded article is problematic due to the difficulty involved withthermally processing such polymers. Renewable polyesters, for example,have a relatively high glass transition temperature and typicallydemonstrate a very high stiffness and tensile modulus, while havingrelatively low impact resistance and low ductility/elongations at break.As an example, polylactic acid has a glass transition temperature ofabout 59° C. and a tensile modulus of about 2 GPa or more. Nevertheless,the tensile elongation (at break) for PLA materials are only about 5%,and the notched impact strength is only about 0.22 J/cm. Such low impactstrength and tensile elongation values significantly limit the use ofsuch polymers in injection molded parts, where a good balance betweenmaterial stiffness and impact strength is required.

As such, a need currently exists for a renewable polyester compositionthat is capable of exhibiting a relatively high impact strength andtensile elongation so that it can be readily employed in injectionmolded articles.

SUMMARY OF THE INVENTION

In accordance with one embodiment of the present invention, a meltblended, thermoplastic composition is disclosed that comprises at leastone rigid renewable polyester having a glass transition temperature ofabout 0° C. or more, from about 1 wt. % to about 30 wt. % of at leastone polymeric toughening additive based on the weight of the renewablepolyester, and from about 0.1 wt. % to about 20 wt. % of at least oneinterphase modifier based on the weight of the renewable polyester. Thethermoplastic composition has a morphology in which a plurality ofdiscrete primary domains are dispersed within a continuous phase, thedomains containing the polymeric toughening additive and the continuousphase containing the renewable polyester. Further, the compositionexhibits an Izod impact strength of about 0.3 Joules per centimeter ormore, measured at 23° C. according to ASTM D256-10 (Method A), and atensile elongation at break of about 10% or more, measured at 23° C.according to ASTM D638-10. Further, the ratio of the glass transitiontemperature of the thermoplastic composition to the glass transitiontemperature of the renewable polyester is from about 0.7 to about 1.3.

In accordance with another embodiment of the present invention, a shapedarticle is disclosed that is formed from a thermoplastic composition.The thermoplastic composition comprises about 70 wt. % or more of atleast one polylactic acid having a glass transition temperature of about0° C. or more, from about 0.1 wt. % to about 30 wt. % of at least onepolymeric toughening additive, and from about 0.1 wt. % to about 20 wt.% of at least one interphase modifier. The molded article exhibits anIzod impact strength of about 0.3 Joules per centimeter or more,measured at 23° C. according to ASTM D256-10 (Method A), and a tensileelongation at break of about 10% or more, measured at 23° C. accordingto ASTM D638-10.

Other features and aspects of the present invention are discussed ingreater detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth more particularly in the remainder of the specification, whichmakes reference to the appended figures in which:

FIG. 1 is a schematic illustration of one embodiment of an injectionmolding apparatus for use in the present invention;

FIG. 2 is an SEM photomicrograph of a sample of Example 1 beforetesting;

FIG. 3 is an SEM photomicrograph of a sample of Example 1 after impacttesting;

FIG. 4 is an SEM photomicrograph of a sample of Example 3 beforetesting;

FIG. 5 is an SEM photomicrograph of a sample of Example 3 after impacttesting; and

FIG. 6 is an SEM photomicrograph of a sample of Example 3 after tensiletesting and oxygen plasma etching.

Repeat use of references characters in the present specification anddrawings is intended to represent same or analogous features or elementsof the invention.

DETAILED DESCRIPTION OF REPRESENTATIVE EMBODIMENTS

Reference now will be made in detail to various embodiments of theinvention, one or more examples of which are set forth below. Eachexample is provided by way of explanation of the invention, notlimitation of the invention. In fact, it will be apparent to thoseskilled in the art that various modifications and variations may be madein the present invention without departing from the scope or spirit ofthe invention. For instance, features illustrated or described as partof one embodiment, may be used on another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncovers such modifications and variations as come within the scope of theappended claims and their equivalents.

Generally speaking, the present invention is directed to a thermoplasticcomposition that contains a rigid renewable polyester and a polymerictoughening additive. The present inventors have discovered that thespecific nature of the components may be carefully controlled to achievea composition having desirable morphological features. Moreparticularly, the toughening additive can be dispersed as discretephysical domains within a continuous matrix of the renewable polyester.During the initial application of an external force at low elongationalstrain, the composition can behave as a monolithic material thatexhibits high rigidity and tensile modulus. However, an increase in thedeformation force and elongational strain causes debonding to occur inthe renewable polyester matrix at those areas located adjacent to thediscrete domains. This can result in the formation of a plurality ofvoids adjacent to the discrete domains that can help to dissipate energyunder load and increase impact strength. To even further increase theability of the composition to dissipate energy in this manner, thepresent inventors have discovered that an interphase modifier may beemployed in the composition that reduces the degree of friction andconnectivity between the toughening additive and renewable polyester andthus enhances the degree and uniformity of debonding. In this manner,the resulting voids can be distributed in a substantially homogeneousfashion throughout the composition. For example, the voids may bedistributed in columns that are oriented in a direction generallyperpendicular to the direction in which a stress is applied. Withoutintending to be limited by theory, it is believed that the presence ofsuch a homogeneously distributed void system can result in insignificant energy dissipation under load and a significantly enhancedimpact strength.

The resulting thermoplastic composition, as well as shaped articles madetherefrom, generally has a high degree of impact strength due to theunique morphology obtained by the present invention. The compositionmay, for instance, possess an Izod notched impact strength of about 0.3Joules per centimeter (“J/cm”) or more, in some embodiments about 0.5J/cm or more, and in some embodiments, from about 0.8 J/cm to about 2.5J/cm, measured at 23° C. according ASTM D256-10 (Method A). The tensileelongation at break may also be relatively high, such as about 10% ormore, in some embodiments about 50% or more, and in some embodiments,from about 100% to about 300%. While achieving a very high degree ofimpact strength and tensile elongation, the present inventors havediscovered that other mechanical properties are not adversely affected.For example, the composition may exhibit a peak stress of from about 10to about 65 Megapascals (“MPa”), in some embodiments from about 15 toabout 55 MPa, and in some embodiments, from about 25 to about 50 MPa; abreak stress of from about 10 to about 65 MPa, in some embodiments fromabout 15 to about 60 MPa, and in some embodiments, from about 20 toabout 55 MPa; and/or a tensile modulus of from about 500 to about 3800MPa, in some embodiments from about 800 MPa to about 3400 MPa, and insome embodiments, from about 1000 MPa to about 3000 MPa. The tensileproperties may be determined in accordance with ASTM D638-10 at 23° C.

Various embodiments of the present invention will now be described inmore detail.

I. Thermoplastic Composition

A. Renewable Polyester

Renewable polyesters typically constitute from about 70 wt. % to about99 wt. %, in some embodiments from about 75 wt. % to about 98 wt. %, andin some embodiments, from about 80 wt. % to about 95 wt. % of thethermoplastic composition. Any of a variety of renewable polyesters maygenerally be employed in the thermoplastic composition, such asaliphatic polyesters, such as polycaprolactone, polyesteramides,polylactic acid (PLA) and its copolymers, polyglycolic acid,polyalkylene carbonates (e.g., polyethylene carbonate),poly-3-hydroxybutyrate (PHB), poly-3-hydroxyvalerate (PHV),poly-3-hydroxybutyrate-co-4-hydroybutyrate,poly-3-hydroxybutyrate-co-3-hydroxyvalerate copolymers (PHBV),poly-3-hydroxybutyrate-co-3-hydroxyhexanoate,poly-3-hydroxybutyrate-co-3-hydroxyoctanoate,poly-3-hydroxybutyrate-co-3-hydroxydecanoate,poly-3-hydroxybutyrate-co-3-hydroxyoctadecanoate, and succinate-basedaliphatic polymers (e.g., polybutylene succinate, polybutylene succinateadipate, polyethylene succinate, etc.); aliphatic-aromatic copolyesters(e.g., polybutylene adipate terephthalate, polyethylene adipateterephthalate, polyethylene adipate isophthalate, polybutylene adipateisophthalate, etc.); aromatic polyesters (e.g., polyethyleneterephthalate, polybutylene terephthalate, etc.); and so forth.

Typically, the thermoplastic composition contains at least one renewablepolyester that is rigid in nature and thus has a relatively high glasstransition temperature. For example, the glass transition temperature(“T_(g)”) may be about 0° C. or more, in some embodiments from about 5°C. to about 100° C., in some embodiments from about 30° C. to about 80°C., and in some embodiments, from about 50° C. to about 75° C. Therenewable polyester may also have a melting temperature of from about140° C. to about 260° C., in some embodiments from about 150° C. toabout 250° C., and in some embodiments, from about 160° C. to about 220°C. The melting temperature may be determined using differential scanningcalorimetry (“DSC”) in accordance with ASTM D-3417. The glass transitiontemperature may be determined by dynamic mechanical analysis inaccordance with ASTM E1640-09.

One particularly suitable rigid polyester is polylactic acid, which maygenerally be derived from monomer units of any isomer of lactic acid,such as levorotory-lactic acid (“L-lactic acid”), dextrorotatory-lacticacid (“D-lactic acid”), meso-lactic acid, or mixtures thereof. Monomerunits may also be formed from anhydrides of any isomer of lactic acid,including L-lactide, D-lactide, meso-lactide, or mixtures thereof.Cyclic dimers of such lactic acids and/or lactides may also be employed.Any known polymerization method, such as polycondensation orring-opening polymerization, may be used to polymerize lactic acid. Asmall amount of a chain-extending agent (e.g., a diisocyanate compound,an epoxy compound or an acid anhydride) may also be employed. Thepolylactic acid may be a homopolymer or a copolymer, such as one thatcontains monomer units derived from L-lactic acid and monomer unitsderived from D-lactic acid. Although not required, the rate of contentof one of the monomer unit derived from L-lactic acid and the monomerunit derived from D-lactic acid is preferably about 85 mole % or more,in some embodiments about 90 mole % or more, and in some embodiments,about 95 mole % or more. Multiple polylactic acids, each having adifferent ratio between the monomer unit derived from L-lactic acid andthe monomer unit derived from D-lactic acid, may be blended at anarbitrary percentage. Of course, polylactic acid may also be blendedwith other types of polymers (e.g., polyolefins, polyesters, etc.).

In one particular embodiment, the polylactic acid has the followinggeneral structure:

One specific example of a suitable polylactic acid polymer that may beused in the present invention is commercially available from Biomer,Inc. of Krailling, Germany) under the name BIOMER™ L9000. Other suitablepolylactic acid polymers are commercially available from Natureworks LLCof Minnetonka, Minn. (NATUREWORKS®) or Mitsui Chemical (LACEA™). Stillother suitable polylactic acids may be described in U.S. Pat. Nos.4,797,468; 5,470,944; 5,770,682; 5,821,327; 5,880,254; and 6,326,458,which are incorporated herein in their entirety by reference thereto forall purposes.

The polylactic acid typically has a number average molecular weight(“M_(n)”) ranging from about 40,000 to about 160,000 grams per mole, insome embodiments from about 50,000 to about 140,000 grams per mole, andin some embodiments, from about 80,000 to about 120,000 grams per mole.Likewise, the polymer also typically has a weight average molecularweight (“M_(w)”) ranging from about 80,000 to about 200,000 grams permole, in some embodiments from about 100,000 to about 180,000 grams permole, and in some embodiments, from about 110,000 to about 160,000 gramsper mole. The ratio of the weight average molecular weight to the numberaverage molecular weight (“M_(w)/M_(n)”), i.e., the “polydispersityindex”, is also relatively low. For example, the polydispersity indextypically ranges from about 1.0 to about 3.0, in some embodiments fromabout 1.1 to about 2.0, and in some embodiments, from about 1.2 to about1.8. The weight and number average molecular weights may be determinedby methods known to those skilled in the art.

The polylactic acid may also have an apparent viscosity of from about 50to about 600 Pascal seconds (Pa·s), in some embodiments from about 100to about 500 Pa·s, and in some embodiments, from about 200 to about 400Pa·s, as determined at a temperature of 190° C. and a shear rate of 1000sec⁻¹. The melt flow rate of the polylactic acid (on a dry basis) mayalso range from about 0.1 to about 40 grams per 10 minutes, in someembodiments from about 0.5 to about 20 grams per 10 minutes, and in someembodiments, from about 5 to about 15 grams per 10 minutes, determinedat a load of 2160 grams and at 190° C.

Some types of neat polyesters (e.g., polylactic acid) can absorb waterfrom the ambient environment such that it has a moisture content ofabout 500 to 600 parts per million (“ppm”), or even greater, based onthe dry weight of the starting polylactic acid. Moisture content may bedetermined in a variety of ways as is known in the art, such as inaccordance with ASTM D 7191-05, such as described below. Because thepresence of water during melt processing can hydrolytically degrade thepolyester and reduce its molecular weight, it is sometimes desired todry the polyester prior to blending. In most embodiments, for example,it is desired that the renewable polyester have a moisture content ofabout 300 parts per million (“ppm”) or less, in some embodiments about200 ppm or less, in some embodiments from about 1 to about 100 ppm priorto blending with the toughening additive. Drying of the polyester mayoccur, for instance, at a temperature of from about 50° C. to about 100°C., and in some embodiments, from about 70° C. to about 80° C.

B. Polymeric Toughening Additive

As indicated above, the thermoplastic composition of the presentinvention also contains a polymeric toughening additive. Due to itspolymeric nature, the toughening additive possesses a relatively highmolecular weight that can help improve the melt strength and stabilityof the thermoplastic composition. Although not required, the polymerictoughening additive may be generally immiscible with the renewablepolyester. In this manner, the toughening additive can better becomedispersed as discrete phase domains within a continuous phase of therenewable polyester. The discrete domains are capable of absorbingenergy that arises from an external force, which increases the overalltoughness and strength of the resulting material. The domains may have avariety of different shapes, such as elliptical, spherical, cylindrical,etc. In one embodiment, for example, the domains have a substantiallyelliptical shape. The physical dimension of an individual domain istypically small enough to minimize the propagation of cracks through thepolymer material upon the application of an external stress, but largeenough to initiate microscopic plastic deformation and allow for shearzones at and around particle inclusions.

While the polymers may be immiscible, the toughening additive maynevertheless be selected to have a solubility parameter that isrelatively similar to that of the renewable polyester. This can improvethe interfacial compatibility and physical interaction of the boundariesof the discrete and continuous phases, and thus reduces the likelihoodthat the composition will fracture. In this regard, the ratio of thesolubility parameter for the renewable polyester to that of thetoughening additive is typically from about 0.5 to about 1.5, and insome embodiments, from about 0.8 to about 1.2. For example, thepolymeric toughening additive may have a solubility parameter of fromabout 15 to about 30 MJoules^(1/2)/m^(3/2), and in some embodiments,from about 18 to about 22 MJoules^(1/2)/m^(3/2), while polylactic acidmay have a solubility parameter of about 20.5 MJoules^(1/2)/m^(3/2). Theterm “solubility parameter” as used herein refers to the “HildebrandSolubility Parameter”, which is the square root of the cohesive energydensity and calculated according to the following equation:

δ=√{square root over (()}(ΔH _(v) −RT)/V _(m))

where:

-   -   Δ Hv=heat of vaporization    -   R=Ideal Gas constant    -   T=Temperature    -   Vm=Molecular Volume

The Hildebrand solubility parameters for many polymers are alsoavailable from the Solubility Handbook of Plastics, by Wyeych (2004),which is incorporated herein by reference.

The polymeric toughening additive may also have a certain melt flow rate(or viscosity) to ensure that the discrete domains and resulting voidscan be adequately maintained. For example, if the melt flow rate of thetoughening additive is too high, it tends to flow and disperseuncontrollably through the continuous phase. This results in lamellar orplate-like domains that are difficult to maintain and also likely toprematurely fracture. Conversely, if the melt flow rate of thetoughening additive is too low, it tends to clump together and form verylarge elliptical domains, which are difficult to disperse duringblending. This may cause uneven distribution of the toughening additivethrough the entirety of the continuous phase. In this regard, thepresent inventors have discovered that the ratio of the melt flow rateof the toughening additive to the melt flow rate of the renewablepolyester is typically from about 0.2 to about 8, in some embodimentsfrom about 0.5 to about 6, and in some embodiments, from about 1 toabout 5. The polymeric toughening additive may, for example, have a meltflow rate of from about 0.1 to about 250 grams per 10 minutes, in someembodiments from about 0.5 to about 200 grams per 10 minutes, and insome embodiments, from about 5 to about 150 grams per 10 minutes,determined at a load of 2160 grams and at 190° C.

In addition to the properties noted above, the mechanicalcharacteristics of the polymeric toughening additive may also beselected to achieve the desired increase in toughness. For example, whena blend of the renewable polyester and toughening additive is appliedwith an external force, shear and/or plastic yielding zones may beinitiated at and around the discrete phase domains as a result of stressconcentrations that arise from a difference in the elastic modulus ofthe toughening additive and renewable polyester. Larger stressconcentrations promote more intensive localized plastic flow at thedomains, which allows them to become significantly elongated whenstresses are imparted. These elongated domains allow the composition toexhibit a more pliable and softer behavior than the otherwise rigidpolyester resin. To enhance the stress concentrations, the tougheningadditive is selected to have a relatively low Young's modulus ofelasticity in comparison to the renewable polyester. For example, theratio of the modulus of elasticity of the renewable polyester to that ofthe toughening additive is typically from about 1 to about 250, in someembodiments from about 2 to about 100, and in some embodiments, fromabout 2 to about 50. The modulus of elasticity of the tougheningadditive may, for instance, range from about 2 to about 500 Megapascals(MPa), in some embodiments from about 5 to about 300 MPa, and in someembodiments, from about 10 to about 200 MPa. To the contrary, themodulus of elasticity of polylactic acid is typically from about 800 MPato about 2000 MPa.

To impart the desired increase in toughness, the polymeric tougheningadditive may also exhibit an elongation at break (i.e., the percentelongation of the polymer at its yield point) greater than the renewablepolyester. For example, the polymeric toughening additive of the presentinvention may exhibit an elongation at break of about 50% or more, insome embodiments about 100% or more, in some embodiments from about 100%to about 2000%, and in some embodiments, from about 250% to about 1500%.

While a wide variety of polymeric additives may be employed that havethe properties identified above, particularly suitable examples of suchpolymers may include, for instance, polyolefins (e.g., polyethylene,polypropylene, polybutylene, etc.); styrenic copolymers (e.g.,styrene-butadiene-styrene, styrene-isoprene-styrene,styrene-ethylene-propylene-styrene, styrene-ethylene-butadiene-styrene,etc.); polytetrafluoroethylenes; polyesters (e.g., recycled polyester,polyethylene terephthalate, etc.); polyvinyl acetates (e.g.,poly(ethylene vinyl acetate), polyvinyl chloride acetate, etc.);polyvinyl alcohols (e.g., polyvinyl alcohol, poly(ethylene vinylalcohol), etc.); polyvinyl butyrals; acrylic resins (e.g., polyacrylate,polymethylacrylate, polymethylmethacrylate, etc.); polyamides (e.g.,nylon); polyvinyl chlorides; polyvinylidene chlorides; polystyrenes;polyurethanes; etc. Suitable polyolefins may, for instance, includeethylene polymers (e.g., low density polyethylene (“LDPE”), high densitypolyethylene (“HDPE”), linear low density polyethylene (“LLDPE”), etc.),propylene homopolymers (e.g., syndiotactic, atactic, isotactic, etc.),propylene copolymers, and so forth.

In one particular embodiment, the polymer is a propylene polymer, suchas homopolypropylene or a copolymer of propylene. The propylene polymermay, for instance, be formed from a substantially isotacticpolypropylene homopolymer or a copolymer containing equal to or lessthan about 10 wt. % of other monomer, i.e., at least about 90% by weightpropylene. Such homopolymers may have a melting point of from about 160°C. to about 170° C.

In still another embodiment, the polyolefin may be a copolymer ofethylene or propylene with another α-olefin, such as a C₃-C₂₀ α-olefinor C₃-C₁₂ α-olefin. Specific examples of suitable α-olefins include1-butene; 3-methyl-1-butene; 3,3-dimethyl-1-butene; 1-pentene; 1-pentenewith one or more methyl, ethyl or propyl substituents; 1-hexene with oneor more methyl, ethyl or propyl substituents; 1-heptene with one or moremethyl, ethyl or propyl substituents; 1-octene with one or more methyl,ethyl or propyl substituents; 1-nonene with one or more methyl, ethyl orpropyl substituents; ethyl, methyl or dimethyl-substituted 1-decene;1-dodecene; and styrene. Particularly desired α-olefin comonomers are1-butene, 1-hexene and 1-octene. The ethylene or propylene content ofsuch copolymers may be from about 60 mole % to about 99 mole %, in someembodiments from about 80 mole % to about 98.5 mole %, and in someembodiments, from about 87 mole % to about 97.5 mole %. The α-olefincontent may likewise range from about 1 mole % to about 40 mole %, insome embodiments from about 1.5 mole % to about 15 mole %, and in someembodiments, from about 2.5 mole % to about 13 mole %.

Exemplary olefin copolymers for use in the present invention includeethylene-based copolymers available under the designation EXACT™ fromExxonMobil Chemical Company of Houston, Tex. Other suitable ethylenecopolymers are available under the designation ENGAGE™, AFFINITY™,DOWLEX™ (LLDPE) and ATTANE™ (ULDPE) from Dow Chemical Company ofMidland, Mich. Other suitable ethylene polymers are described in U.S.Pat. No. 4,937,299 to Ewen et al.; U.S. Pat. No. 5,218,071 to Tsutsui etal.; U.S. Pat. No. 5,272,236 to Lai, et al.; and U.S. Pat. No. 5,278,272to Lai, et al., which are incorporated herein in their entirety byreference thereto for all purposes. Suitable propylene copolymers arealso commercially available under the designations VISTAMAXX™ fromExxonMobil Chemical Co. of Houston, Tex.; FINA™ (e.g., 8573) fromAtofina Chemicals of Feluy, Belgium; TAFMER™ available from MitsuiPetrochemical Industries; and VERSIFY™ available from Dow Chemical Co.of Midland, Mich. Other examples of suitable propylene polymers aredescribed in U.S. Pat. No. 6,500,563 to Datta, et al.; U.S. Pat. No.5,539,056 to Yang, et al.; and U.S. Pat. No. 5,596,052 to Resconi, etal., which are incorporated herein in their entirety by referencethereto for all purposes.

Any of a variety of known techniques may generally be employed to formthe olefin copolymers. For instance, olefin polymers may be formed usinga free radical or a coordination catalyst (e.g., Ziegler-Natta).Preferably, the olefin polymer is formed from a single-site coordinationcatalyst, such as a metallocene catalyst. Such a catalyst systemproduces ethylene copolymers in which the comonomer is randomlydistributed within a molecular chain and uniformly distributed acrossthe different molecular weight fractions. Metallocene-catalyzedpolyolefins are described, for instance, in U.S. Pat. No. 5,571,619 toMcAlpin et al.; U.S. Pat. No. 5,322,728 to Davis et al.; U.S. Pat. No.5,472,775 to Obijeski et al.; U.S. Pat. No. 5,272,236 to Lai et al.; andU.S. Pat. No. 6,090,325 to Wheat, et al., which are incorporated hereinin their entirety by reference thereto for all purposes. Examples ofmetallocene catalysts include bis(n-butylcyclopentadienyl)titaniumdichloride, bis(n-butylcyclopentadienyl)zirconium dichloride,bis(cyclopentadienyl)scandium chloride, bis(indenyl)zirconiumdichloride, bis(methylcyclopentadienyl)titanium dichloride,bis(methylcyclopentadienyl)zirconium dichloride, cobaltocene,cyclopentadienyltitanium trichloride, ferrocene, hafnocene dichloride,isopropyl(cyclopentadienyl,-1-flourenyl)zirconium dichloride,molybdocene dichloride, nickelocene, niobocene dichloride, ruthenocene,titanocene dichloride, zirconocene chloride hydride, zirconocenedichloride, and so forth. Polymers made using metallocene catalyststypically have a narrow molecular weight range. For instance,metallocene-catalyzed polymers may have polydispersity numbers(M_(w)/M_(n)) of below 4, controlled short chain branching distribution,and controlled isotacticity.

Regardless of the materials employed, the relative percentage of thepolymeric toughening additive in the thermoplastic composition isselected to achieve the desired properties without significantlyimpacting the renewability of the resulting composition. For example,the toughening additive is typically employed in an amount of from about1 wt. % to about 30 wt. %, in some embodiments from about 2 wt. % toabout 25 wt. %, and in some embodiments, from about 5 wt. % to about 20wt. % of the thermoplastic composition, based on the weight of therenewable polyesters employed in the composition. The concentration ofthe toughening additive in the entire thermoplastic composition maylikewise constitute from about 0.1 wt. % to about 30 wt. %, in someembodiments from about 0.5 wt. % to about 25 wt. %, and in someembodiments, from about 1 wt. % to about 20 wt. %.

C. Interphase Modifier

An interphase modifier is also employed in the thermoplastic compositionto alter the interaction between the toughening additive and therenewable polyester matrix. The modifier is generally in a liquid orsemi-solid form at room temperature (e.g., 25° C.) so that it possessesa relatively low viscosity, allowing it to be more readily incorporatedinto the thermoplastic composition and to easily migrate to the polymersurfaces. In this regard, the kinematic viscosity of the interphasemodifier is typically from about 0.7 to about 200 centistokes (“cs”), insome embodiments from about 1 to about 100 cs, and in some embodiments,from about 1.5 to about 80 cs, determined at 40° C. In addition, theinterphase modifier is also typically hydrophobic so that it has anaffinity for the polymer toughening additive, resulting in a change inthe interfacial tension between the renewable polyester and thetoughening additive. By reducing physical forces at the interfacesbetween the polyester and the toughening additive, it is believed thatthe low viscosity, hydrophobic nature of the modifier can helpfacilitate debonding from the polyester matrix upon the application ofan external force. As used herein, the term “hydrophobic” typicallyrefers to a material having a contact angle of water in air of about 40°or more, and in some cases, about 60° or more. In contrast, the term“hydrophilic” typically refers to a material having a contact angle ofwater in air of less than about 40°. One suitable test for measuring thecontact angle is ASTM D5725-99 (2008).

Suitable hydrophobic, low viscosity interphase modifiers may include,for instance, silicones, silicone-polyether copolymers, aliphaticpolyesters, aromatic polyesters, alkylene glycols (e.g., ethyleneglycol, diethylene glycol, triethylene glycol, tetraethylene glycol,propylene glycol, polyethylene glycol, polypropylene glycol,polybutylene glycol, etc.), alkane diols (e.g., 1,3-propanediol,2,2-dimethyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol,1,5-pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,6 hexanediol,1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol,2,2,4,4-tetramethyl-1,3-cyclobutanediol, etc.), amine oxides (e.g.,octyldimethylamine oxide), fatty acid esters, etc. One particularlysuitable interphase modifier is polyether polyol, such as commerciallyavailable under the trade name PLURIOL® WI from BASF Corp. Anothersuitable modifier is a partially renewable ester, such as commerciallyavailable under the trade name HALLGREEN® IM from Hallstar.

Although the actual amount may vary, the interphase modifier istypically employed in an amount of from about 0.1 wt. % to about 20 wt.%, in some embodiments from about 0.5 wt. % to about 15 wt. %, and insome embodiments, from about 1 wt. % to about 10 wt. % of thethermoplastic composition, based on the weight of the renewablepolyesters employed in the composition. The concentration of theinterphase modifier in the entire thermoplastic composition may likewiseconstitute from about 0.05 wt. % to about 20 wt. %, in some embodimentsfrom about 0.1 wt. % to about 15 wt. %, and in some embodiments, fromabout 0.5 wt. % to about 10 wt. %.

When employed in the amounts noted above, the interphase modifier has acharacter that enables it to readily migrate to the interfacial surfaceof the polymers and facilitate debonding without disrupting the overallmelt properties of the thermoplastic composition. For example, theinterphase modifier does not typically have a plasticizing effect on thepolymer by reducing its glass transition temperature. Quite to thecontrary, the present inventors have discovered that the glasstransition temperature of the thermoplastic composition may besubstantially the same as the initial renewable polyester. In thisregard, the ratio of the glass temperature of the composition to that ofthe polyester is typically from about 0.7 to about 1.3, in someembodiments from about 0.8 to about 1.2, and in some embodiments, fromabout 0.9 to about 1.1. The thermoplastic composition may, for example,have a glass transition temperature of from about 35° C. to about 80°C., in some embodiments from about 40° C. to about 80° C., and in someembodiments, from about 50° C. to about 65° C. The melt flow rate of thethermoplastic composition may also be similar to that of the renewablepolyester. For example, the melt flow rate of the composition (on a drybasis) may be from about 0.1 to about 70 grams per 10 minutes, in someembodiments from about 0.5 to about 50 grams per 10 minutes, and in someembodiments, from about 5 to about 25 grams per 10 minutes, determinedat a load of 2160 grams and at a temperature of 190° C.

D. Compatibilizer

As indicated above, the polymeric toughening additive is generallyselected so that it has a solubility parameter relatively close to thatof the renewable polyester. Among other things, this can enhance thecompatibility of the phases and improve the overall distribution of thediscrete domains within the continuous phase. Nevertheless, in certainembodiments, a compatibilizer may optionally be employed to furtherenhance the compatibility between the renewable polyester and thepolymeric toughening additive. This may be particularly desirable whenthe polymeric toughening additive possesses a polar moiety, such aspolyurethanes, acrylic resins, etc. When employed, the compatibilizerstypically constitute from about 0.5 wt. % to about 20 wt. %, in someembodiments from about 1 wt. % to about 15 wt. %, and in someembodiments, from about 1.5 wt. % to about 10 wt. % of the thermoplasticcomposition. One example of a suitable compatibilizer is afunctionalized polyolefin. The polar component may, for example, beprovided by one or more functional groups and the non-polar componentmay be provided by an olefin. The olefin component of the compatibilizermay generally be formed from any linear or branched α-olefin monomer,oligomer, or polymer (including copolymers) derived from an olefinmonomer, such as described above.

The functional group of the compatibilizer may be any group thatprovides a polar segment to the molecule. Particularly suitablefunctional groups are maleic anhydride, maleic acid, fumaric acid,maleimide, maleic acid hydrazide, a reaction product of maleic anhydrideand diamine, methylnadic anhydride, dichloromaleic anhydride, maleicacid amide, etc. Maleic anhydride modified polyolefins are particularlysuitable for use in the present invention. Such modified polyolefins aretypically formed by grafting maleic anhydride onto a polymeric backbonematerial. Such maleated polyolefins are available from E. I. du Pont deNemours and Company under the designation Fusabond®, such as the PSeries (chemically modified polypropylene), E Series (chemicallymodified polyethylene), C Series (chemically modified ethylene vinylacetate), A Series (chemically modified ethylene acrylate copolymers orterpolymers), or N Series (chemically modified ethylene-propylene,ethylene-propylene diene monomer (“EPDM”) or ethylene-octene).Alternatively, maleated polyolefins are also available from ChemturaCorp. under the designation Polybond® and Eastman Chemical Company underthe designation Eastman G series.

In certain embodiments, the compatibilizer may also be reactive. Oneexample of such a reactive compatibilizer is a polyepoxide modifier thatcontains, on average, at least two oxirane rings per molecule. Withoutintending to be limited by theory, it is believed that such polyepoxidemolecules can induce a reaction of the renewable polyester under certainconditions, thereby improving its melt strength without significantlyreducing glass transition temperature. The reaction may involve chainextension, side chain branching, grafting, copolymer formation, etc.Chain extension, for instance, may occur through a variety of differentreaction pathways. For instance, the modifier may enable a nucleophilicring-opening reaction via a carboxyl terminal group of the renewablepolyester (esterification) or via a hydroxyl group (etherification).Oxazoline side reactions may likewise occur to form esteramide moieties.Through such reactions, the molecular weight of the renewable polyestermay be increased to counteract the degradation often observed duringmelt processing. While it is desirable to induce a reaction with therenewable polyester as described above, the present inventors havediscovered that too much of a reaction can lead to crosslinking betweenpolyester backbones. If such crosslinking is allowed to proceed to asignificant extent, the resulting polymer blend can become brittle anddifficult to shape into a material with the desired strength andelongation properties.

In this regard, the present inventors have discovered that polyepoxidemodifiers having a relatively low epoxy functionality are particularlyeffective, which may be quantified by its “epoxy equivalent weight.” Theepoxy equivalent weight reflects the amount of resin that contains onemolecule of an epoxy group, and it may be calculated by dividing thenumber average molecular weight of the modifier by the number of epoxygroups in the molecule. The polyepoxide modifier of the presentinvention typically has a number average molecular weight from about7,500 to about 250,000 grams per mole, in some embodiments from about15,000 to about 150,000 grams per mole, and in some embodiments, fromabout 20,000 to 100,000 grams per mole, with a polydispersity indextypically ranging from 2.5 to 7. The polyepoxide modifier may containless than 50, in some embodiments from 5 to 45, and in some embodiments,from 15 to 40 epoxy groups. In turn, the epoxy equivalent weight may beless than about 15,000 grams per mole, in some embodiments from about200 to about 10,000 grams per mole, and in some embodiments, from about500 to about 7,000 grams per mole.

The polyepoxide may be a linear or branched, homopolymer or copolymer(e.g., random, graft, block, etc.) containing terminal epoxy groups,skeletal oxirane units, and/or pendent epoxy groups. The monomersemployed to form such polyepoxides may vary. In one particularembodiment, for example, the polyepoxide modifier contains at least oneepoxy-functional (meth)acrylic monomeric component. As used herein, theterm “(meth)acrylic” includes acrylic and methacrylic monomers, as wellas salts or esters thereof, such as acrylate and methacrylate monomers.For example, suitable epoxy-functional (meth)acrylic monomers mayinclude, but are not limited to, those containing 1,2-epoxy groups, suchas glycidyl acrylate and glycidyl methacrylate. Other suitableepoxy-functional monomers include allyl glycidyl ether, glycidylethacrylate, and glycidyl itoconate.

The polyepoxide typically has a relatively high molecular weight, asindicated above, so that it can not only result in chain extension ofthe renewable polyester, but also help to achieve the desired blendmorphology. The resulting melt flow rate of the polymer is thustypically within a range of from about 10 to about 200 grams per 10minutes, in some embodiments from about 40 to about 150 grams per 10minutes, and in some embodiments, from about 60 to about 120 grams per10 minutes, determined at a load of 2160 grams and at a temperature of190° C.

If desired, additional monomers may also be employed in the polyepoxideto help achieve the desired molecular weight. Such monomers may vary andinclude, for example, ester monomers, (meth)acrylic monomers, olefinmonomers, amide monomers, etc. In one particular embodiment, forexample, the polyepoxide modifier includes at least one linear orbranched α-olefin monomer, such as those having from 2 to 20 carbonatoms and preferably from 2 to 8 carbon atoms. Specific examples includeethylene, propylene, 1-butene; 3-methyl-1-butene; 3,3-dimethyl-1-butene;1-pentene; 1-pentene with one or more methyl, ethyl or propylsubstituents; 1-hexene with one or more methyl, ethyl or propylsubstituents; 1-heptene with one or more methyl, ethyl or propylsubstituents; 1-octene with one or more methyl, ethyl or propylsubstituents; 1-nonene with one or more methyl, ethyl or propylsubstituents; ethyl, methyl or dimethyl-substituted 1-decene;1-dodecene; and styrene. Particularly desired α-olefin comonomers areethylene and propylene.

Another suitable monomer may include a (meth)acrylic monomer that is notepoxy-functional. Examples of such (meth)acrylic monomers may includemethyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate,n-butyl acrylate, s-butyl acrylate, i-butyl acrylate, t-butyl acrylate,n-amyl acrylate, i-amyl acrylate, isobomyl acrylate, n-hexyl acrylate,2-ethylbutyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-decylacrylate, methylcyclohexyl acrylate, cyclopentyl acrylate, cyclohexylacrylate, methyl methacrylate, ethyl methacrylate, 2-hydroxyethylmethacrylate, n-propyl methacrylate, n-butyl methacrylate, i-propylmethacrylate, i-butyl methacrylate, n-amyl methacrylate, n-hexylmethacrylate, i-amyl methacrylate, s-butyl-methacrylate, t-butylmethacrylate, 2-ethylbutyl methacrylate, methylcyclohexyl methacrylate,cinnamyl methacrylate, crotyl methacrylate, cyclohexyl methacrylate,cyclopentyl methacrylate, 2-ethoxyethyl methacrylate, isobornylmethacrylate, etc., as well as combinations thereof.

In one particularly desirable embodiment of the present invention, thepolyepoxide modifier is a terpolymer formed from an epoxy-functional(meth)acrylic monomeric component, α-olefin monomeric component, andnon-epoxy functional (meth)acrylic monomeric component. For example, thepolyepoxide modifier may be poly(ethylene-co-methylacrylate-co-glycidylmethacrylate), which has the following structure:

wherein, x, y, and z are 1 or greater.

The epoxy functional monomer may be formed into a polymer using avariety of known techniques. For example, a monomer containing polarfunctional groups may be grafted onto a polymer backbone to form a graftcopolymer. Such grafting techniques are well known in the art anddescribed, for instance, in U.S. Pat. No. 5,179,164, which isincorporated herein in its entirety by reference thereto for allpurposes. In other embodiments, a monomer containing epoxy functionalgroups may be copolymerized with a monomer to form a block or randomcopolymer using known free radical polymerization techniques, such ashigh pressure reactions, Ziegler-Natta catalyst reaction systems, singlesite catalyst (e.g., metallocene) reaction systems, etc.

The relative portion of the monomeric component(s) may be selected toachieve a balance between epoxy-reactivity and melt flow rate. Moreparticularly, high epoxy monomer contents can result in good reactivitywith the renewable polyester, but too high of a content may reduce themelt flow rate to such an extent that the polyepoxide modifier adverselyimpacts the melt strength of the polymer blend. Thus, in mostembodiments, the epoxy-functional (meth)acrylic monomer(s) constitutefrom about 1 wt. % to about 25 wt. %, in some embodiments from about 2wt. % to about 20 wt. %, and in some embodiments, from about 4 wt. % toabout 15 wt. % of the copolymer. The α-olefin monomer(s) may likewiseconstitute from about 55 wt. % to about 95 wt. %, in some embodimentsfrom about 60 wt. % to about 90 wt. %, and in some embodiments, fromabout 65 wt. % to about 85 wt. % of the copolymer. When employed, othermonomeric components (e.g., non-epoxy functional (meth)acrylic monomers)may constitute from about 5 wt. % to about 35 wt. %, in some embodimentsfrom about 8 wt. % to about 30 wt. %, and in some embodiments, fromabout 10 wt. % to about 25 wt. % of the copolymer. One specific exampleof a suitable polyepoxide modifier that may be used in the presentinvention is commercially available from Arkema under the name LOTADER®AX8950 or AX8900. LOTADER® AX8950, for instance, has a melt flow rate of70 to 100 g/10 min and has a glycidyl methacrylate monomer content of 7wt. % to 11 wt. %, a methyl acrylate monomer content of 13 wt. % to 17wt. %, and an ethylene monomer content of 72 wt. % to 80 wt. %.

In addition to controlling the type and relative content of the monomersused to form the polyepoxide modifier, the overall weight percentage mayalso be controlled to achieve the desired benefits. For example, if themodification level is too low, the desired increase in melt strength andmechanical properties may not be achieved. The present inventors havealso discovered, however, that if the modification level is too high,molding may be restricted due to strong molecular interactions (e.g.,crosslinking) and physical network formation by the epoxy functionalgroups. Thus, the polyepoxide modifier is typically employed in anamount of from about 0.05 wt. % to about 10 wt. %, in some embodimentsfrom about 0.1 wt. % to about 8 wt. %, in some embodiments from about0.5 wt. % to about 5 wt. %, and in some embodiments, from about 1 wt. %to about 3 wt. %, based on the weight of the renewable polyestersemployed in the composition. The polyepoxide modifier may alsoconstitute from about 0.05 wt. % to about 10 wt. %, in some embodimentsfrom about 0.05 wt. % to about 8 wt. %, in some embodiments from about0.1 wt. % to about 5 wt. %, and in some embodiments, from about 0.5 wt.% to about 3 wt. %, based on the total weight of the composition.

When employed, the polyepoxide modifier may also influence themorphology of the thermoplastic composition in a way that furtherenhances its reactivity with the renewable polyester. More particularly,the resulting morphology may have a plurality of discrete domains of thepolyepoxide modifier distributed throughout a continuous polyestermatrix. These “secondary” domains may have a variety of differentshapes, such as elliptical, spherical, cylindrical, etc.

Regardless of the shape, however, the size of an individual secondarydomain, after blending, is small to provide an increased surface areafor reaction with the renewable polyester. For example, the size of asecondary domain (e.g., length) typically ranges from about 10 to about1000 nanometers, in some embodiments from about 20 to about 800nanometers, in some embodiments from about 40 to about 600 nanometers,and in some embodiments from about 50 to about 400 nanometers. As notedabove, the toughening additive also forms discrete domains within thepolyester matrix, which are considered in the “primary” domains of thecomposition. Of course, it should be also understood that domains may beformed by a combination of the polyepoxide, toughening additive, and/orother components of the blend.

In addition to polyepoxides, other reactive compatibilizers may also beemployed in the present invention, such as oxazoline-functionalizedpolymers, cyanide-functionalized polymers, etc. When employed, suchreactive compatibilizers may be employed within the concentrations notedabove for the polyepoxide modifier. In one particular embodiment, anoxazoline-grafted polyolefin may be employed that is a polyolefingrafted with an oxazoline ring-containing monomer. The oxazoline mayinclude a 2-oxazoline, such as 2-vinyl-2-oxazoline (e.g.,2-isopropenyl-2-oxazoline), 2-fatty-alkyl-2-oxazoline (e.g., obtainablefrom the ethanolamide of oleic acid, linoleic acid, palmitoleic acid,gadoleic acid, erucic acid and/or arachidonic acid) and combinationsthereof. In another embodiment, the oxazoline may be selected fromricinoloxazoline maleinate, undecyl-2-oxazoline, soya-2-oxazoline,ricinus-2-oxazoline and combinations thereof, for example. In yetanother embodiment, the oxazoline is selected from2-isopropenyl-2-oxazoline, 2-isopropenyl-4,4-dimethyl-2-oxazoline andcombinations thereof.

E. Other Components

One beneficial aspect of the present invention is that good mechanicalproperties (e.g., elongation) may be provided without the need forconventional plasticizers, such as solid or semi-solid polyethyleneglycol, such as available from Dow Chemical under the name Carbowax™).The thermoplastic composition may be substantially free of suchplasticizers. Nevertheless, it should be understood that plasticizersmay be used in certain embodiments of the present invention. Whenutilized, however, the plasticizers are typically present in an amountof less than about 10 wt. %, in some embodiments from about 0.1 wt. % toabout 5 wt. %, and in some embodiments, from about 0.2 wt. % to about 2wt. % of the thermoplastic composition. Of course, other ingredients maybe utilized for a variety of different reasons. For instance, materialsthat may be used include, without limitation, catalysts, pigments,antioxidants, stabilizers, surfactants, waxes, solid solvents, fillers,nucleating agents (e.g., titanium dioxide, calcium carbonate, etc.),particulates, and other materials added to enhance the processability ofthe thermoplastic composition. When utilized, it is normally desiredthat the amounts of these additional ingredients are minimized to ensureoptimum compatibility and cost-effectiveness. Thus, for example, it isnormally desired that such ingredients constitute less than about 10 wt.%, in some embodiments less than about 8 wt. %, and in some embodiments,less than about 5 wt. % of the thermoplastic composition.

II. Blending

The raw materials (e.g., renewable polyester, toughening additive, andinterphase modifier) may be blended using any of a variety of knowntechniques. In one embodiment, for example, the raw materials may besupplied separately or in combination. For instance, the raw materialsmay first be dry mixed together to form an essentially homogeneous drymixture. The raw materials may likewise be supplied eithersimultaneously or in sequence to a melt processing device thatdispersively blends the materials. Batch and/or continuous meltprocessing techniques may be employed. For example, a mixer/kneader,Banbury mixer, Farrel continuous mixer, single-screw extruder,twin-screw extruder, roll mill, etc., may be utilized to blend and meltprocess the materials. Particularly suitable melt processing devices maybe a co-rotating, twin-screw extruder (e.g., ZSK-30 extruder availablefrom Wemer & Pfleiderer Corporation of Ramsey, New Jersey or a ThermoPrism™ USALAB 16 extruder available from Thermo Electron Corp., Stone,England). Such extruders may include feeding and venting ports andprovide high intensity distributive and dispersive mixing. For example,the raw materials may be fed to the same or different feeding ports ofthe twin-screw extruder and melt blended to form a substantiallyhomogeneous melted mixture. If desired, other additives may also beinjected into the polymer melt and/or separately fed into the extruderat a different point along its length. Alternatively, the additives maybe pre-blended with the renewable polyester, toughening additive, and/orinterphase modifier.

Regardless of the particular processing technique chosen, the rawmaterials are blended under sufficient shear/pressure and heat to ensuresufficient dispersion, but not so high as to adversely reduce the sizeof the discrete domains so that they are incapable of achieving thedesired toughness and elongation. For example, blending typically occursat a temperature of from about 180° C. to about 260° C., in someembodiments from about 185° C. to about 250° C., and in someembodiments, from about 190° C. to about 240° C. Likewise, the apparentshear rate during melt processing may range from about 10 seconds⁻¹ toabout 3000 seconds⁻¹, in some embodiments from about 50 seconds⁻¹ toabout 2000 seconds⁻¹, and in some embodiments, from about 100 seconds⁻¹to about 1200 seconds⁻¹. The apparent shear rate is equal to 4Q/πR³,where Q is the volumetric flow rate (“m³/s”) of the polymer melt and Ris the radius (“m”) of the capillary (e.g., extruder die) through whichthe melted polymer flows. Of course, other variables, such as theresidence time during melt processing, which is inversely proportionalto throughput rate, may also be controlled to achieve the desired degreeof homogeneity.

To achieve the desired shear conditions (e.g., rate, residence time,shear rate, melt processing temperature, etc.), the speed of theextruder screw(s) may be selected with a certain range. Generally, anincrease in product temperature is observed with increasing screw speeddue to the additional mechanical energy input into the system. Forexample, the screw speed may range from about 50 to about 500revolutions per minute (“rpm”), in some embodiments from about 70 toabout 300 rpm, and in some embodiments, from about 100 to about 200 rpm.This may result in a temperature that is sufficient high to disperse thetoughening additive and interphase modifier without adversely impactingthe size of the resulting domains. The melt shear rate, and in turn thedegree to which the polymers are dispersed, may also be increasedthrough the use of one or more distributive and/or dispersive mixingelements within the mixing section of the extruder. Suitabledistributive mixers for single screw extruders may include, forinstance, Saxon, Dulmage, Cavity Transfer mixers, etc. Likewise,suitable dispersive mixers may include Blister ring, Leroy/Maddock, CRDmixers, etc. As is well known in the art, the mixing may be furtherimproved by using pins in the barrel that create a folding andreorientation of the polymer melt, such as those used in Buss Kneaderextruders, Cavity Transfer mixers, and Vortex Intermeshing Pin (VIP)mixers.

III. Shaped Articles

Due to its unique and beneficial properties, the thermoplasticcomposition of the present invention is well suited for use in shapedarticles, and particularly those having a relatively small thickness.For example, the article may have a thickness of about 100 micrometersto about 50 millimeters, in some embodiments from about 200 micrometersto about 10 millimeters, in some embodiments from about 400 micrometersto about 5 millimeters, and in some embodiments, from about 500micrometers to about 2 millimeters.

The shaped article may be formed using any of a variety of techniquesknown in the art, such as profile extrusion, extrusion blow molding,injection molding, rotational molding, compression molding, etc., aswell as combinations of the foregoing. Regardless of the processselected, the thermoplastic composition of the present invention may beused alone to form the article, or in combination with other polymericcomponents to form a shaped articles. For example, the thermoplasticcomposition can be profile extruded as a core while other polymer(s) canbe extruded as a “skin” or external layer. In another embodiment, otherpolymer(s) may be injected or transferred into a mold during aninjection molding process to form a skin layer around a core. Examplesof machines suitable for co-injection, sandwich or two-component moldinginclude machines produced by Presma Corp., Northeast Mold & Plastics,Inc. Although not required, the core of the shaped article is typicallyformed from the thermoplastic composition of the present invention andthe skin layer is typically formed from a different polymer (e.g.,polyolefins, polyesters, polyamides, etc.) that enhances surface andbulk and bonding properties for intended use.

Referring to FIG. 1, for example, one particular embodiment of asingle-component injection molding apparatus or tool 10 that may beemployed in the present invention is shown in more detail. In thisembodiment, the apparatus 10 includes a first mold base 12 and a secondmold base 14, which together define an article or component-definingmold cavity 16. Each of the mold bases 12 and 14 includes one or morecooling lines 18 through which a cooling liquid such as water flows tocool the apparatus 10 during use. The molding apparatus 10 also includesa resin flow path that extends from an outer exterior surface 20 of thefirst mold half 12 through a sprue 22 to the article-defining moldcavity 16. The resin flow path may also include a runner and a gate,both of which are not shown for purposes of simplicity. The moldingapparatus 10 also includes one or more ejector pins 24 slidably securedwithin the second mold half 14 that helps to define the article-definingcavity 16 in the closed position of the apparatus 10, as indicated inFIG. 1. The ejector pin 24 operates in a well known fashion to remove amolded article or component from the article-defining cavity 16 in theopen position of the molding apparatus 10.

The thermoplastic composition may be directly injected into the moldingapparatus 10 using techniques known in the art. For example, the moldingmaterial may be supplied in the form of pellets to a feed hopperattached to a barrel that contains a rotating screw (not shown). As thescrew rotates, the pellets are moved forward and undergo extremepressure and friction, which generates heat to melt the pellets.Electric heater bands (not shown) attached to the outside of the barrelmay also assist in the heating and temperature control during themelting process. For example, the bands may be heated to a temperatureof from about 200° C. to about 260° C., in some embodiments from about230° C. to about 255° C., and in some embodiments, from about 240° C. toabout 250° C. Upon entering the molding cavity 16, the molding materialis solidified by the cooling liquid flowing through the lines 18. Thecooling liquid may, for example, be at a temperature (the “moldingtemperature”) of from about 5° C. to about 50° C., in some embodimentsfrom about 10° C. to about 40° C., and in some embodiments, from about15° C. to about 30° C.

The shaped articles may have a variety of different sizes andconfigurations. For instance, the article may be used to form dispensers(e.g., for paper towels), packaging materials (e.g., food packaging,medical packaging, etc.), medical devices, such as surgical instruments(e.g., scalpels, scissors, retractors, suction tubes, probes, etc.);implants (e.g., bone plates, prosthetics, plates, screws, etc.);containers or bottles; and so forth. The article may also be used toform various parts used in “personal care” applications. For instance,in one particular embodiment, the article is used to form a wet wipecontainer. The configuration of the container may vary as is known inthe art, such as described in U.S. Pat. No. 5,687,875 to Watts, et al.;U.S. Pat. No. 6,568,625 to Faulks, et al.; U.S. Pat. No. 6,158,614 toHaines, et al.; U.S. Pat. No. 3,973,695 to Ames; U.S. Pat. No. 6,523,690to Buck, et al.; and U.S. Pat. No. 6,766,919 to Huang, et al., which areincorporated herein in their entirety by reference thereto for allpurposes. Wipes for use with the container, e.g., wet wipes, may bearranged in any manner that provides convenient and reliable dispensingand that assists the wet wipes in not becoming overly dry. For example,the wet wipes may be arranged in the container as a plurality ofindividual wipes in a stacked configuration to provide a stack of wetwipes that may or may not be individually folded. The wet wipes can beindividual wet wipes which are folded in a c-fold configuration, z-foldconfiguration, connected to adjacent wipes by a weakened line or othernon-interfolded configurations as are known to those skilled in the art.Alternatively, the individual wet wipes can be interfolded such that theleading and trailing end edges of successive wipes in the stackedconfiguration overlap. In each of these non-interfolded and interfoldedconfigurations, the leading end edge of the following wet wipe isloosened from the stack by the trailing end edge of the leading wet wipeas the leading wet wipe is removed by the user from the dispenser orpackage. For example, representative wet wipes for use with theinvention are described in U.S. Pat. No. 6,585,131 to Huang, et al. andU.S. Pat. No. 6,905,748 to Sosalla, which are incorporated herein intheir entirety by reference thereto for all purposes.

The present invention may be better understood with reference to thefollowing examples.

Test Methods Melt Flow Rate:

The melt flow rate (“MFR”) is the weight of a polymer (in grams) forcedthrough an extrusion rheometer orifice (0.0825-inch diameter) whensubjected to a load of 2160 grams in 10 minutes, typically at 190° C. or230° C. Unless otherwise indicated, melt flow rate is measured inaccordance with ASTM Test Method D1239 with a Tinius Olsen ExtrusionPlastometer.

Thermal Properties:

The glass transition temperature (T_(g)) may be determined by dynamicmechanical analysis (DMA) in accordance with ASTM E1640-09. A Q800instrument from TA Instruments may be used. The experimental runs may beexecuted in tension/tension geometry, in a temperature sweep mode in therange from −120° C. to 150° C. with a heating rate of 3° C./min. Thestrain amplitude frequency may be kept constant (2 Hz) during the test.Three (3) independent samples may be tested to get an average glasstransition temperature, which is defined by the peak value of the tan δcurve, wherein tan 6 is defined as the ratio of the loss modulus to thestorage modulus (tan δ=E″/E′).

The melting temperature may be determined by differential scanningcalorimetry (DSC). The differential scanning calorimeter may be a DSCQ100 Differential Scanning Calorimeter, which was outfitted with aliquid nitrogen cooling accessory and with a UNIVERSAL ANALYSIS 2000(version 4.6.6) analysis software program, both of which are availablefrom T.A. Instruments Inc. of New Castle, Del. To avoid directlyhandling the samples, tweezers or other tools are used. The samples areplaced into an aluminum pan and weighed to an accuracy of 0.01 milligramon an analytical balance. A lid is crimped over the material sample ontothe pan. Typically, the resin pellets are placed directly in theweighing pan.

The differential scanning calorimeter is calibrated using an indiummetal standard and a baseline correction is performed, as described inthe operating manual for the differential scanning calorimeter. Amaterial sample is placed into the test chamber of the differentialscanning calorimeter for testing, and an empty pan is used as areference. All testing is run with a 55-cubic centimeter per minutenitrogen (industrial grade) purge on the test chamber. For resin pelletsamples, the heating and cooling program is a 2-cycle test that beganwith an equilibration of the chamber to −30° C., followed by a firstheating period at a heating rate of 10° C. per minute to a temperatureof 200° C., followed by equilibration of the sample at 200° C. for 3minutes, followed by a first cooling period at a cooling rate of 10° C.per minute to a temperature of −30° C., followed by equilibration of thesample at −30° C. for 3 minutes, and then a second heating period at aheating rate of 10° C. per minute to a temperature of 200° C. Alltesting is run with a 55-cubic centimeter per minute nitrogen(industrial grade) purge on the test chamber.

The results are evaluated using the UNIVERSAL ANALYSIS 2000 analysissoftware program, which identified and quantified the glass transitiontemperature (T_(g)) of inflection, the endothermic and exothermic peaks,and the areas under the peaks on the DSC plots. The glass transitiontemperature is identified as the region on the plot-line where adistinct change in slope occurred, and the melting temperature isdetermined using an automatic inflection calculation.

Notched Izod Impact Strength:

Notched Impact strength of injection molded Izod bars were determined byfollowing ASTM D256-10 Method A (Standard Test Methods for Determiningthe Izod Pendulum Impact Resistance of Plastics). Izod bars wereconditioned for 40+ hours at 23° C.±2° C. at 50%±10% relative humiditybefore testing in the same conditions. The pendulum had a capacity of 2ft·lbs. Injection molded Izod test specimens had a width 12.70±0.20 mmand thickness of 3.2±0.05 mm.

Unnotched Izod Impact Strength

Unnotched Impact Strength of injection molded Izod bars were determinedby following ASTM D 4812-06 (Unnotched Cantilever Beam impact Strengthof Plastics). Izod bars were conditioned for 40+ hours at 23° C.±2° C.at 50%±10% relative humidity before being testing in the sameconditions. The pendulum had a capacity of 2 ft·lbs or 5 ft lbs.Injection molded Izod test specimens had a width 12.70±0.20 mm andthickness of 3.2±0.05 mm.

Tensile Properties:

Modulus was determined utilizing a MTS 810 hydraulic tensile frame topull injection molded Type I dog bones as described in ASTM D638-10.Specimens were conditioned at 23° C.±2° C. and 50%±10% relative humidityfor not less than 40 hours. Test conditions were at 23° C.±2° C. and50%±10% relative humidity. Tensile frame grips were at a nominal gagelength of 115 mm. Specimens were pulled at a rate of 50 mm/min (87.7%.min deformation). Five (5) specimens were tested for each composition. Acomputer program called TestWorks 4 was used to collect data duringtesting and to generate a stress versus strain curve from which theaverage modulus of five specimens was determined.

Peak stress, break stress, elongation at break, and energy per volume atbreak were determined using a MTS Synergie 200 tensile frame to pullinjection molded Type V dog bones at described in ASTM D638-10.Specimens were conditioned at 23° C.±2° C. at 50%±10% relative humidityfor not less than 40 hours. Test conditions were at 23° C.±2° C. at20%±10% relative humidity. Tensile frame grips were at a nominal gagelength of 25.4 mm. Specimens were pulled at a rate of 8.4 mm/min(87.7%/min deformation). Five (5) specimens were tested for eachcomposition. A computer program called TestWorks 4 was used to collectdata during testing and to generate a stress versus strain curve fromwhich the average peak stress, break stress, elongation at break, andenergy per volume at break were determined.

High Speed Puncture Property

High Speed Puncture Property of Average Total Energy was determined byfollowing guidelines of ASTM D3763-10 Standard Test Method for HighSpeed Puncture Properties of Plastics Using Load and DisplacementSensors. Specimens were prepared by forming injection molded 63.5±0.5 mmdiameter disk with a thickness of 1.09±0.2 mm. Injection molding wascarried out by flood feeding pellets into a Spritzgiessautomaten BOY 22Dinjection molding device at a barrel temperature of 225° C. to 195° C.,mold temperature of approximately 27° C., and cycle time ofapproximately 40 seconds. The ASTM D3763 test speed was 3.3meters/second, the test conditions were 23° C.±2° C./50%±10% RH,utilizing Intron Dynatup 8250 with Impulse Data Acquisition System v2.2.1, Tup Diameter of 12.7 mm, with based and top support clampassembly having 40 mm diameter. Reported for Examples 1, 4, 5, 7, 11,and 16 are the Average Total Energy (Joules).

Shrinkage from Mold Dimensions

Shrinkage from injection mold cavity dimensions was determined byfollowing ASTM D955-08 Standard Test Method of Measuring Shrinkage fromMold Dimensions of Thermoplastics. Injection mold cavity had a length(L_(m)) dimension of 126.78 mm and width (W_(m)) dimension of 12.61 mm,which conforms to ASTM D955-08 Type A specimen. The average length(L_(s)) and width (W_(s)) of the 5 test specimens were measured after24±1 hours, 48±1 hours, or 96±1 hours after specimens had been removedfrom the mold. Shrinkage in the length direction (S) was calculated byS_(l)=(L_(m)−L_(s))×100/L_(m). Shrinkage of the width direction (S_(w))was calculated by S_(w)=(W_(m)−W_(s))×100/W_(m).

Moisture Content

Moisture content may be determined using an Arizona InstrumentsComputrac Vapor Pro moisture analyzer (Model No. 3100) in substantialaccordance with ASTM D 7191-05, which is incorporated herein in itsentirety by reference thereto for all purposes. The test temperature(§X2.1.2) may be 130° C., the sample size (§X2.1.1) may be 2 to 4 grams,and the vial purge time (§X2.1.4) may be 30 seconds. Further, the endingcriteria (§X2.1.3) may be defined as a “prediction” mode, which meansthat the test is ended when the built-in programmed criteria (whichmathematically calculates the end point moisture content) is satisfied.

Example 1

Polylactic acid (PLA 6201D having a melt flow rate of 10 g/10 min at190° C., Natureworks®) was formed into an injected molded part as acontrol. The shrinkage from the mold length dimension after 24 hours and48 hours were 0.2% and 0.2%, respectively. The shrinkage from the moldwidth dimension after 24 and 48 hours were −0.5% and 0.1%.

Example 2

The ability to form injection molded parts from a blend of 88.7 wt. %polylactic acid (PLA 6201D having a melt flow rate of 10 g/10 min at190° C., Natureworks®) 9.9 wt. % of a toughening additive and 1.4%polyepoxide modifier was demonstrated. The toughening additive wasVISTAMAXX™ 2120 (ExxonMobil), which is a polyolefin copolymer/elastomerwith a melt flow rate of 29 g/10 min (190° C., 2160 g) and a density of0.866 g/cm³. The polyepoxide modifier was poly(ethylene-co-methylacrylate-co-glycidyl methacrylate) (LOTADER® AX8950, Arkema) having amelt flow rate of 70-100 g/10 min (190° C./2160 g), a glycidylmethacrylate content of 7 to 11 wt. %, methyl acrylate content of 13 to17 wt. %, and ethylene content of 72 to 80 wt. %. The polymers were fedinto a co-rotating, twin-screw extruder (ZSK-30, diameter of 30 mm,length of 1328 millimeters) for compounding that was manufactured byWerner and Pfleiderer Corporation of Ramsey, New Jersey. The extruderpossessed 14 zones, numbered consecutively 1-14 from the feed hopper tothe die. The first barrel zone #1 received the resins via gravimetricfeeder at a total throughput of 15 pounds per hour. The die used toextrude the resin had 3 die openings (6 millimeters in diameter) thatwere separated by 4 millimeters. Upon formation, the extruded resin wascooled on a fan-cooled conveyor belt and formed into pellets by a Conairpelletizer. The extruder screw speed was 200 revolutions per minute(“rpm”).

The pellets were then flood fed into an injection molded device(Spritzgiessautomaten BOY 22D) and molded into a part at a barreltemperature of approximately 210±25° C., mold temperature ofapproximately 20±13° C., and cycle time of approximately 45±25 seconds.The shrinkage from the mold length dimension after 24 hours and 48 hourswas 0.4% and 0.4%, respectively. The shrinkage from the mold widthdimension after 24 and 48 hours was 0.0% and 0.2%.

Example 3

Parts were injection molded as described in Example 2, except that theblend contained 85.3 wt. % polylactic acid (PLA 6201D, Natureworks®),9.5 wt. % of toughening additive VISTAMAXX™ 2120 (ExxonMobil), 1.4 wt. %polyepoxide modifier (LOTADER® AX8950, Arkema), and 3.8 wt. % interphasemodifier (PLURIOL® WI 285 from BASF). The PLURIOL® WI-285 was added viainjector pump into barrel zone #2. The shrinkage from the mold lengthand width dimensions after 96 hours was −0.4% and 0.3%, respectively.

Example 4

Parts were injection molded as described in Example 3, except thatLOTADER® AX8900 (Arkema) was employed as the polyepoxide modifier.

Example 5

Parts were injection molded as described in Example 2, except that theblend contained 84.5 wt. % polylactic acid (PLA 6201 D, Natureworks®),9.4 wt. % of toughening additive VISTAMAXX™ 2120 (ExxonMobil), 1.4 wt. %polyepoxide modifier (LOTADER® AX8900, Arkema), and 4.7 wt. % interphasemodifier HALLGREEN® IM-8830 from Hallstar. The HALLGREEN® IM-8830 wasadded via injector pump into barrel zone #2.

Example 6

Parts were injection molded as described in Example 4, except that thetoughening additive was EXCEED™ 3512CB resin (ExxonMobil).

Example 7

Parts were injection molded as described in Example 4, except that thetoughening additive was ESCORENE™ UL EVA 7720 (ExxonMobil).

Example 8

Parts were injection molded as described in Example 2, except that theblend contained 88.7 wt. % polylactic acid (PLA 6201D, Natureworks®),9.9 wt. % of toughening additive polypropylene, PP 3155 (ExxonMobil),and 1.4 wt. % polyepoxide modifier (LOTADER® AX8950, Arkema).

Example 9

Parts were injection molded as described in Example 8, except that theblend contained 87.4 wt. % polylactic acid (PLA 6201D, Natureworks®),9.7 wt. % of toughening additive VISTAMAXX™ 2120 (ExxonMobil) and about2.9 wt. % of maleic anhydride grafted polypropylene, Fusabond 353D(ExxonMobil).

Example 10

Parts were injection molded as described in Example 4, except that thetoughening additive was INFUSE™ 9507 olefin block copolymer resin (DowChemical Company).

Example 11

Parts were injection molded as described in Example 4, except that thetoughening additive was VECTOR* 4113A styrenic block copolymer resin(Dexco Polymers LP).

Example 12

Parts were injection molded as described in Example 11, except that theinterphase modifier was HALLGREEN® IM-8830 from Hallstar.

Example 13

Parts were injection molded as described in Example 7, except that theinterphase modifier was HALLGREEN® IM-8830 from Hallstar.

Example 14

Parts were injection molded as described in Example 2, except that theblend contained 80.6 wt. % polylactic acid (PLA 6201D, Natureworks®),14.2 wt. % of toughening additive ESCORENE™ UL EVA 7720 (ExxonMobil),1.4 wt. % polyepoxide modifier (LOTADER® AX8900, Arkema), and 3.8 wt. %interphase modifier (PLURIOL® WI 285 from BASF). The PLURIOL® WI-285 wasadded via injector pump into barrel zone #2.

Example 15

Parts were injection molded as described in Example 14, except that theblend contained 90.1 wt. % polylactic acid (PLA 6201D, Natureworks®),4.7 wt. % of toughening additive ESCORENE™ UL EVA 7720 (ExxonMobil), 1.4wt. % polyepoxide modifier (LOTADER® AX8900, Arkema), and 3.8 wt. %interphase modifier (PLURIOL® WI 285 from BASF). The PLURIOL® WI-285 wasadded via injector pump into barrel zone #2.

Example 16

Parts were injection molded as described in Example 2, except thatLOTADER® AX8900 (Arkema) was employed as the polyepoxide modifier.

The injection molded parts of Examples 1-16 were then tested for impactstrength, high speed puncture properties, and tensile properties in themanner described above. The results are set forth below.

Energy Notched High Per Izod Unnotched Speed Avg. Avg. Avg. VolumeImpact Impact Puncture Avg. Peak Break Elongation At Strength StrengthProperty Modulus Stress Stress at Break Break Ex Desc (J/cm) (J/cm)(Joules) (MPa) (MPa) (MPa) (%) (J/cm³) 1 PLA 0.26 1.79 0.30 3712 67.657.0 11.8 5.7 2 PLA VIM 0.45 2.03 — 2933 55.0 27.9 19.5 6.3 LOT 3 PLAVIM 0.56 1.98 — 2788 35.8 33.1 165.4 49.2 LOT WI 4 PLA VFM 0.71 — 1.782511 36.5 35.5 200.3 57.8 LOT WI 5 PLA VTM 1.88 — 2.91 2373 31.8 30.6196.8 50.0 LOT IM 6 PLA 0.61 5.84 — 2318 41.2 41.2 236.6 74.1 Exceed ™LOT WI 7 PLA EVA 1.27 — 3.32 2247 382 37.9 236.8 68.4 LOT WI 8 PLA PP0.31 — — 3270 62.0 49.7 8.3 3.4 LOT 9 PLA VTM — 2.59 — 2922 52.3 41.88.0 2.8 FUS 10 PLA 0.70 — — 2604 37.5 37.3 209.5 61.2 INFUSE ™ LOT WI 11PLA 0.70 — 4.16 2584 36.0 35.7 205.1 58.1 VECTOR LOT WI 12 PLA 0.94 — —2600 29.7 24.1 116.8 27.1 VECTOR LOT IM 13 PLA EVA 0.95 — — 2554 35.835.8 210.0 58.8 LOT IM 14 PLA 1.76 — — 2148 30.7 28.4 174.4 43.6 14.2%EVA LOT WI 15 PLA 4.7% 0.33 — — 2516 44.4 43.7 231.1 74.8 EVA LOT WI 16PLA VTM — — 1.13 2427 55.2 30.9 62.0 19.1 LOT

As indicated above, the samples containing an interphase modifier(Samples 3-7 and 10-15) generally exhibited a much higher impactresistance than Sample 1 (containing only polylactic acid), Samples 2,8-9, and 16 (containing only polylactic acid, toughening additive, andpolyepoxide modifier). SEM photomicrographs were also taken of Example 1(containing only polylactic acid) and 3 (containing interphase modifier)before and after testing. The results are shown in FIGS. 2-6. FIGS. 2-3,for example, show samples formed in Example 1 before and after impacttesting. FIG. 4 shows a sample formed in Example 3 prior toimpact/tensile testing. As shown, the PLA matrix of Example 3 hasunderwent debonding, which resulted in the formation of a plurality ofvoids adjacent to discrete domains of the Vistamaxx™ polymer. FIGS. 5-6likewise show the sample of Example 3 after impact and tensile testing,respectively (FIG. 6 was obtained after oxygen plasma etching). As shownin FIG. 6, for instance, nearly parallel linear openings are formed thatare oriented perpendicular to the stress application direction andextending across the width of the material samples exposed to externalstress. The openings have a plurality of voided features, as well as aplurality of elongated ligaments that together help dissipate stress.

Example 17

Polyethylene terephthalate (Crystar 4434 from Du Pont) was extruded andthen formed into an injected molded part as a control.

Example 18

The ability to form injection molded parts a blend of 88.7 wt. %polyethylene terephthalate (Crystar 4434 from Du Pont) 9.9 wt. % of atoughening additive and 1.4% polyepoxide modifier was demonstrated. Thetoughening additive was VISTAMAXX™ 2120 (ExxonMobil), which is apolyolefin copolymer/elastomer with a melt flow rate of 29 g/10 min(190° C., 2160 g) and a density of 0.866 g/cm³. The polyepoxide modifierwas poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) (LOTADER®AX8900, Arkema) having a melt flow rate of 6 g/10 min (190° C./2160 g),a glycidyl methacrylate content of 8 wt. %, methyl acrylate content of24 wt. %, and ethylene content of 68 wt. %. The polymers were fed into aco-rotating, twin-screw extruder (ZSK-30, diameter of 30 mm, length of1328 millimeters) for compounding that was manufactured by Werner andPfleiderer Corporation of Ramsey, New Jersey. The extruder possessed 14zones, numbered consecutively 1-14 from the feed hopper to the die. Thefirst barrel zone #1 received the resins via gravimetric feeder at atotal throughput of 15 pounds per hour. The die used to extrude theresin had 3 die openings (6 millimeters in diameter) that were separatedby 4 millimeters. Upon formation, the extruded resin was cooled on afan-cooled conveyor belt and formed into pellets by a Conair pelletizer.The extruder screw speed was 200 revolutions per minute (“rpm”).

The pellets were then flood fed into an injection molded device(Spritzgiessautomaten BOY 22D) and molded into a part at a barreltemperature of approximately 285±45° C., mold temperature ofapproximately 27±10° C., and cycle time of approximately 35±10 seconds.

Example 19

Parts were injection molded as described in Example 18, except that theblend contained 85.3 wt. % polyethylene terephthalate (Crystar 4434 fromDu Pont), 9.5 wt. % of toughening additive VISTAMAXX™ 2120 (ExxonMobil),1.4 wt. % polyepoxide modifier (LOTADER® AX8900, Arkema), and 3.8 wt. %internal interphase modifier (PLURIOL® WI 285 from BASF). The PLURIOL®WI-285 was added via injector pump into barrel zone #2.

Example 20

Parts were injection molded as described in Example 19, except that thetoughening additive was ESCORENE™ UL EVA 7720 (ExxonMobil).

The injection molded parts of Examples 17-20 were then tested for impactstrength and tensile properties in the manner described above. Theresults are set forth below.

Avg. Avg. Energy Per Avg. Peak Beak Avg. Volume Modulus Stress StressElongation At Break Example Description (MPa) (MPa) (MPa) at Break %(J/cm³) 17 PET 2125 57.9 32.6 116.0 34.9 18 PET VTM 1614 49.5 47.6 300.5101.0 LOT 19 PET VTM 1570 36.9 25.8 92.0 23.6 LOT WI 20 PET EVA 165138.7 22.2 27.7 6.6 LOT WI

Example 21

Parts were injection molded as described in Example 2, except that theblend contained 96.2 wt. % polylactic acid (PLA 6201D, Natureworks®) and3.8 wt. % PLURIOL® WI 285 from BASF. The PLURIOL® WI-285 was added viainjector pump into barrel zone #2.

Example 22

Parts were injection molded as described in Example 2, except that theblend contained 95.2 wt. % polylactic acid (PLA 6201 D, Natureworks®)and 4.7 wt. % HALLGREEN® IM-8830 from Hallstar. The HALLGREEN® IM-8830was added via injector pump into barrel zone #2.

Example 23

Parts were injection molded as described in Example 2, except that theblend contained 96.2 wt. % polylactic acid (PLA 6201D, Natureworks®) and3.8 wt. % Carbowax™ PEG 3350 polyethylene glycol from Dow Chemical.

Glass transition temperature was determined for Examples 1, 21-23, 16,4, and 5 as described above. The results are set forth below.

T_(g) (tanδ) T_(g) tanδ EXAMPLE Description T_(g) (E″) [° C.] [° C.]ratio 1 PLA 70.6 78.5 — 21 PLA WI 63.8 72 0.92 22 PLA IM 61.9 70.8 0.9023 PLA PEG 63.2 73 0.93 16 PLA VTM LOT 69.3 77.4 0.99 4 PLA VTM LOT WI64.1 71.8 0.91 5 PLA VTM LOT IM 65.4 73.2 0.93

The above data demonstrates that the ratio of the glass transitiontemperature of the thermoplastic composition to the glass transitiontemperature of the renewable polyester is between 0.7 to about 1.3.

While the invention has been described in detail with respect to thespecific embodiments thereof, it will be appreciated that those skilledin the art, upon attaining an understanding of the foregoing, mayreadily conceive of alterations to, variations of, and equivalents tothese embodiments. Accordingly, the scope of the present inventionshould be assessed as that of the appended claims and any equivalentsthereto.

1-27. (canceled)
 28. A melt blended, thermoplastic compositioncomprising: a rigid polyester having a glass transition temperature ofabout 0° C. or more, wherein the rigid polyester is polylactic acid,polyethylene terephthalate, or a combination thereof, wherein thepolyester constitutes about 70 wt. % or more of the thermoplasticcomposition; from about 1 wt. % to about 30 wt. % of at least onepolymeric toughening additive based on the weight of the polyester; fromabout 0.1 wt. % to about 20 wt. % of at least one interphase modifierbased on the weight of the polyester; and wherein the thermoplasticcomposition has a morphology in which a plurality of discrete primarydomains are dispersed within a continuous phase, the domains containingthe polymeric toughening additive and the continuous phase containingthe polyester, and wherein the ratio of the glass transition temperatureof the thermoplastic composition to the glass transition temperature ofthe polyester is from about 0.7 to about 1.3.
 29. The thermoplasticcomposition of claim 28, wherein polyester and the thermoplasticcomposition have a glass transition temperature of from about 50° C. toabout 75° C.
 30. The thermoplastic composition of claim 28, wherein theratio of the solubility parameter for the polyester to the solubilityparameter of the polymeric toughening additive is from about 0.5 toabout 1.5.
 31. The thermoplastic composition of claim 30, wherein thepolymeric toughening additive has a solubility parameter of from about15 to about 30 MJoules^(1/2)/m^(3/2).
 32. The thermoplastic compositionof claim 28, wherein the ratio of the melt flow rate for the polyesterto the melt flow rate of the polymeric toughening additive is from about0.2 to about
 8. 33. The thermoplastic composition of claim 28, whereinthe ratio of the Young's modulus elasticity of the polyester to theYoung's modulus of elasticity of the polymeric toughening additive isfrom about 2 to about
 500. 34. The thermoplastic composition of claim28, wherein the polymeric toughening additive includes a polyolefin. 35.The thermoplastic composition of claim 34, wherein the polyolefin is apropylene homopolymer, propylene/α-olefin copolymer, ethylene/α-olefincopolymer, or a combination thereof.
 36. The thermoplastic compositionof claim 28, wherein the interphase modifier has a kinematic viscosityof from about 0.7 to about 200 centistokes, determined at a temperatureof 40° C.
 37. The thermoplastic composition of claim 28, wherein theinterphase modifier is hydrophobic.
 38. The thermoplastic composition ofclaim 28, wherein the interphase modifier is a silicone,silicone-polyether copolymer, aliphatic polyester, aromatic polyester,alkylene glycol, alkane diol, amine oxide, fatty acid ester, or acombination thereof.
 39. The thermoplastic composition of claim 28,wherein the discrete domains have a length of from about 0.05micrometers to about 30 micrometers.
 40. The thermoplastic compositionof claim 28, further comprising a compatibilizer, polyepoxide modifier,or both.
 41. The thermoplastic composition of claim 28, wherein thecomposition comprises a polyepoxide modifier that includes anepoxy-functional (meth)acrylic monomeric component.
 42. Thethermoplastic composition of claim 41, wherein the polyepoxide modifieris poly(ethylene-co-methacrylate-co-glycidyl methacrylate).
 43. Thethermoplastic composition of claim 28, wherein the composition exhibitsan Izod impact strength of about 0.3 Joules per centimeter or more,measured at 23° C. according to ASTM D256-10 (Method A), and a tensileelongation at break of about 10% or more, measured at 23° C. accordingto ASTM D638-10.
 44. The thermoplastic composition of claim 28, whereinthe composition exhibits an Izod notched impact strength of from about0.8 Joules per centimeter to about 2.5 Joules per centimeter, measuredat 23° C. according to ASTM D256-10 (Method A).
 45. The thermoplasticcomposition of claim 28, wherein the composition exhibits a tensileelongation at break of from about 100% to about 300%, measured at 23° C.according to ASTM D638-10.